Polyolefins are very important items of commerce, being used for myriad uses, such as molding resins, films, ropes, composites, fibers, elastomers, etc. Suitability for any particular use is dependent on the polymer properties, for instance whether the polymer is elastomeric or thermoplastic. One method of polymerization of these olefins is by coordination polymerization, use of a polymerization catalyst containing a transition metal, the metal usually being thought of as coordinating to one or more species during the polymerization process.
Whether any particular transition metal compound is an olefin polymerization catalyst usually depends on the metal chosen and what is coordinated (such as various ligands) to the metal before and during the polymerization. Various transition metal compounds may or may not be active catalysts for a particular (type of) olefin, and the resulting polymer structures may vary. Other factors such as the efficiency and rate of polymerization may vary. Therefore, new transition metal catalysts for olefin polymerizations are constantly being sought.